Improvement sn steam-engines



' i2 Sheets-Sheet I. G. B. DOW Steam-Engine.

No. 206,708. Patented Aug. 6, |878.

? l Fig .1.

Witnesses .i Inventor ffm? M@ @M-Vwf; ..2

N PETERS. PHOTO-UTHDWPHER, WAHXNGYON. D C.

' l 2 Sheetsx-Sheet 2. n G. E; DOW.

Steam-Engine.

No. 206,708; Patented Aug'. 6. 1878.`

l To all whom it may camera:v

UNITED `S rnrns GEORGE E. DOV, 0F SAN.FRANOISCO, CALIFORNIA.

lMPRVEMENT lN'STEAMfENGlNES.

l.Seneicatii..fntirrlirilgf part oiluotters Patent NorflOS.. dated August 6 1878; application-tiled May 16, 18.78.

) Be it known that I, Geenen E. Dow, of the city and county of San, Francisco, and State of California, have invented an Improved Steam- Engine; and I do hereby declarey the following to be a full, clear, and exa-ct description thereof,

reference being had to the accompanying draw'- 1n men s in directiactmg steam-engines 5 and it consists in the elnnh yinent ot'` a mechanism bywhichtne main steam-valves which oper;

ate the 4main piston may be moved with a degree oi? .positiveness corresponding with any desired increase irl the speed of the piston, so that a complete movement of the main valve anda full opening of the ports may be ei'-` fceted when the conditions require it mostthat 'witlihigh speeds,4 Y

Y lt also consistenti a means oioperating by which the changel of stroke is accomplished without shock, whatever may bethe speedor pressure; and', iinally, in a reduction of the waste room between the valve and piston, so

fthat the ports @all be short and direct, and

no small ports communicate with' thesteamchest in such afmanner as to form pockets that willbwome foul from the preciptat ion of impure lubricants..

In order tofmore fully explain my invc'ntion, reference is made to the accompanying drawings, infwhich'Fignre lis a longitudinal section et' my cylinder. steam-chest and ports. Fig. 3 is a transverse section through .fr in Fig. l. Fig. et is a transverse section through y y in Fig. 1.

Ilhe saine letters of reference in each-of the drawings refer to the same parts.

yfig-'is the cylinder of a direct-acting engine, and B B are the cylinder-heads, which I Vhave plemental valves Gr; or, if found desirable, the chambers. maybe formed in the body ot' the;

invention relates to certain improve- Fie". 2 is a plainof showniintheapresentcase extending inte the endsof the cylinder, so as to formA .cylinder or steam-chest, the object being to construct them as conveniently as possible.

Theinain valve H is made long, and each end is fitted to control the steam and exhaust ports I J at that end of the cylinder, so that by this construction am enabled' to shorten the ports and makeverylittle waste room between the steam-chest and cylinder. This main valve is operated by means of a supplemental piston, K, which moves in its cylinder L in the manner yusual to this class of engines.

' The supplemental valves G have each a groove turned around them, and these. grooves, when the valves are seated, form a connection between the passage M from the supplemental cylinder and the main eilianst N through the short passage l?.

A passage, Q., leads .from the chamber G into ...the supplemental vulve-chamber `dt the bottom, and another passage, lt, leads from the side of this valve-chamber to the supplemental cylinder.

The operation will then be 'as follows: The piston E moving in the direction shown by the arrows, will approach the end until the extension D enters the chamber G, and the steam compressed by this movement will elevate the supplemental valve G until the groove is above the line of the exhaust-passage M andthe valve closes it. This action opens the steam- 4pzmsage R, and allows steam to enter the supplcmental cylinder and move its piston K, so as -to reverse the main valve. These movements are all accomplished, as has been de-` scribed, wlien the engine is at a high speed; but, when it is moving slowly the compression in the chamber may not be enough to insure a perfect operation of the valves. I have, therefore, made a passage, S,which leads from the main steam-cylinder into the 'passage Q, I`so that this passage S will be `opened for the entrance-of .livel steam from behind the main piston to raise the valve G just as the stroke is finished.

The movement of the supplemental piston' moves the main valve H and opens the steamport I 'at that end. At the same time this valve exposes a small port, T, which leads to the' extreme end or annulus around'the chamber C, against which the main-piston stops, so

as to start it easily and softly. Steam can enter` through the main steam-port I. A small port, U, leads from the steam-port 'l to the chamber of the supplemental valve G, above the valve, so that if this valve does not close by gravitation the pressure of the steam will close it, and the pressure thus admitted will balance any pressure against the opposite end through the passage Q. The moment the valve G drops 'to its seat the groove around it comes into line with the passages M and I), and thus allows the steam'to exhaust from the supplemental cylinder, so that the supplemental pis-A ton is free from pressure the instant after it' has lmoved the main Valve and during the stroke of the main piston. As the passage S is only exposed to the admission of steam just as the stroke of the piston is nished, it will be closed by the first impulse of the ,return movement of the piston before the main steamport I is disclosed, and before the extension D of the piston has moved out of its chamber,

so as to open the port Q-in fact while the pis' ton E is being moved bythe action ofthe steam which is admitted through the small port T.

. It will thus be seen that the movement of my pistony must 'always be completed. before thenecessary action ofthe valves, and while at a low rate of speed live steam is always admitted through the port S to insure the move.- ment of the supplemental piston and main valve, so when a high speed is attained, the compression Within the chambers C, by means of the extensions/D of the piston, will be suttcient to instantaneously open the valves :to

their fullest capacity, and there will be no Wiredrawing of the steam through the small ports, nor a consequent partial opening of valves a-'nd lack of power at a time when it is most needed.. There are no levers or moving parts which will Wear or become less ei'ective by service 5 in fact the parts will all wear tight.

Hill

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valves G, provided with ports P, with tllrX-i haast-passages M and steam-passage R and the passage Q, all constructed and arranged substantially as and for the purpose herein described. n Y

2. The grooved valve G, movin g iu the cham.- ber F, having the supplemental exhaust-passages M P and steam-passage It, and the passage Q, communicating with the main cylinder, in combination with the steam passage U, v

leading above the valve G, substantially as and for the purpose herein described..

3. The main piston E, with its extensions D and the chambers C at the end ofthe cylinder, in combination with the main valve H,With its tivo sets of steam and exhaust passages I and J, and the small steam-port T, opening into thel main cylinder, substantially as and for the purpose herein described.

4. The piston E, with its extensions l) and the chambers C at the ends of the cylinder, in combination with the supplemental valve G, as shown, and the passage Q, and the passages S,I"ro1n th'e'actin side of the piston, substan- 'tially as and for the purpose herein described.

In witness 1whereof I hereunto set my hand' and seal.

GEORGE EDWIN DOW. fr.. sul Witnesses:

FRANK A. BROOKS, WALTER. C. BEA'rrn. 

